Air-cooled surface condenser



Jan. 15, 1963 F. SCHULENBERG 3,073,575

AIR-COOLED SURFACE CONDENSER Filed Sept. 5, 1957 7 Sheets-Sheet 2 {gli}'Eig l L @H Iglu E' l E EN@ h l' E El m E @l M l MS Fig. 2

NVENTOR ATTORNEY Jan. 15, 1963 F. scHuLENBERG 3,073,575

AIR-COOLED SURFACE CONDENSER Filed Sept. 5, 1957 7 Sheets-Sheet 5 J ZwHTTORNEH Jan. 15, 1963 F. scHuLl-:NBERG 3,073,575

AIR-comu SURFACE coNnENsER Filed Sept. 5, 1957 '7 Sheets-Sheet 4 in J#n, u' l; I l

' l ,li yd iIRI INVENTOF? HTTORNEJ F. SCHULENBERG AIR-COOLED SURFACECONDENSER '7 Sheets-Sheet 5 /NvefNroR RTTRNEQ/ Jan. 15, 1963 Filed Sept.5, 1957 Jan. 15, 1963 F. scHULl-:NBERG 3,073,575

AIR-COOLED SURFACE CONDENSER Filed Sept. 5, 1957 7 Sheets-Sheet 6 /lvVEN T0 R Jan. 15, 1963 Filed Sept. 5, 1957 F. SCHULENBERG AIR-COOLEDSURFACE CONDENSER 7 Sheets-Sheet 7 Fig. l0

/NVEN TOR #TTD RNES/ 3,073,575 Patented Jan. 15, 1963 3,073,575AIR-CGLED SURFACE CONDENSER Franz Schulenberg, Bochum, Germany, assgnorto Gea- Luftltuhler-Gesellschaft m.h.H., Bochum, Germany, a

firm

Filed Sept. 5, 1957, Ser. No. 682,238 7 Claims. (Cl. 16S- 146) Thepresent invention relates to a surface condenser with a plurality ofcondenser elements connected in parallel as regards the steam to becondensed and cooled externally by a current of air maintained inpositive circulation, in which condenser each condenser element has atleast two rows of condenser tubes arranged substantially parallel toeach other and one behind the other at a distance apart in the directionof flow of the cooling air. The condenser tubes of each condenserelement are at the same time connected in parallel to a .common steamdistribution chamber :and to a common condensate collecting chamber. Thevaporous medium to be condensed, for example water vapor, is fed to thesteam distribution chambers of the individual condenser elements throughat least one `connection piece of a steam distribution conduit. Two tofour or even more rows of condenser tubes are arranged one behind theother in the ow direction of the cooling air. The condenser tubes aregenerally constructed as ribbed tubts and may be of circular orelliptical cross section. The condenser tubes are brushed on their outersi-de by a current of cooling air drawn from the atmosphere andpositively kept movingl for example by means of propeller blowers.

In the condensers of this type hitherto known the condenser tubes in allthe rows arranged one behind the other in the direction of ow of thecooling air receive the same quantities of steam. As the tubes in theindividual rows possess similar heat-exchanging surfaces, the objectionarises that, owing to the drop in temperature becoming less from row torow in the direction of flow between the temperature of the steamentering the distribution chamber and that of the cooling air, thecondensation in the individual rows varies very considerably. Whereas,for example, in the first row of tubes brushed by the cooling air thewhole of the steam is already condensed at a relatively great distancefrom the end of the tube leading into the condensate collecting chamber,in the row of tubes last brushed by the current of cooling air thecondensation process is only terminated in the neighborhood of the endof the tube leading to the condensate collecting chamber. Consequently,in the rows of tubes first brushed by the air current only a portion ofthe tube length is utilized for the condensation of the steam, whereasin the remaining section of the length of these tubes the condensateundergoes unnecessary undercooling. This cooling of the condensate belowthe condensation point has been found extremely disadvantageousespecially in the case of low atmospheric temperatures, particularlyheavy frost, because in the rows of tubes first brushed by the coolingair the condensate is cooled far below freezing point so that thesetubes become completely choked by ice plugs. When the tubes of the rowof tubes first brushed by the current of cooling air have become chokedby freezing up, the cooling air comes within the range of the second rowof tubes at a lower temperature, with the result that also in thesetubes the boundary between the condensation range and the undercoolingrange is displaced towards the steam admission end owing to the greaterdrop in temperature available, and ice plugs also form there. The sameprocedure repeats itself at very low atmospheric temperatures of, forexample, about 20 C., possibly also in the next following rows of tubesso that the condenser either becomes frozen upv entirely or itsthroughput capacity is reduced to a able extent.

In order to avoid the above-mentioned objections it is proposed,according to lthe invention, to adapt the heatvery considerexchangingsurfaces of the condenser tubes in the rows of tubes arranged one behindthe other in the direction of flow and/ or the steam distribution to therows of tubes to the actually 4available drop in temperature between thesteam admission temperature, in the neighborhood of the steamdistribution chamber, and the cooling air temperature in such a mannerthat in all the rows of tubes the condensation is completed lat a shortdistance from the ends of the tubes leading into the condensatecollecting chamber. This presents the advantage that subcooling of thecondensate is avoided and the formation of ice plugs in cold weathercannot occur. Furthermore, a far better utilization of the availableheat-exchaning surface is obtained, which is advantageous not only inthe case of particularly low atmospheric temperatures but also in thecase of higher atmospheric temperatures. Finally, by this arrangement,while subcooled condensate enters the condensate collecting chamber fromthe rows of tubes first brushed by the cooling air current, thecondensation process in the last row of tubes situated at the end of theair current possibly in the neighborhood of the ends of the tubesleading into the condensate collecting chamber will not have terminatedcompletely and some steam will still be sucked out of these tubes by theair exhausting device.

The invention can be applied for example in .such a manner that, whileusing condenser tubes of similar length, similar passage cross sectionand with similar heat-exchanging surfaces, at least the tubes in the rowfirst brushed by the current of cooling air 4reecive a far greaterquantity of steam, for example 1/4 to 2/3 more than the tubes of therows of tubes arranged behind them in the direction in which the coolingair flows. It is, however, particularly advantageous yfor the quantitiesof steam admitted to the tubes of the rows of tubes arranged one behindthe other in the direction of flow to be substantially proportionatelyequal to the drop in temperature actually available between the steamadmission temperature in the neighborhood of the distribution chamberand the mean cooling air temperature in the range of the actual row oftubes. In order to obtain such steam distribution, devices forthrottling the steam admission can be coordinated to the ends of thetubes leading into the steam distribution chamber. These devices mayconsist, for example, of nozzles or diaphragms fitted, if necessaryexchangeably tted, in the tube ends leading from the steam distributionchamber. Such throttling arrangements are not necessary in the row 'oftubes first brushed by the cooling air, which tubes each receive amaximum quantity of steam.

The object of the invention can also be attained in that, when usingcondenser tubes of uniform passage cross section and uniform length,which receive the same quantities of steam, at least the tubes of therow of tubes rst brushed by the cooling air current have aheat-exchanging surface which, in relation to the quantity of steampassed through, is considerably smaller, for example by 1A to Va, thanthe tubes of the rows of tubes following thereafter. However, it isparticularly advantageous in this case for the heat-exchanging surfaceof the tubes in the rows of tubes `arranged one 4behind the other in thedirection in which the cooling air flows, to be dimensionedsubstantially inversely proportional to the actually available drop intemperatures between the steam admission temperature in the region ofthe distribution chamber and the mean cooling air temperature in theregion of the actual row of tubes. To obtain a different heat-exchangingsurface in the case of the tubes of the rows of tubes arrangedfollowing'each other in the direction in which the cooling air flows,the surface area and/or the spacing of the ribs in the individual rowsof tubes can, when ribbed tubes are employed, be different.

According to another feature of the invention the tubes in the row oftubes irst brushed by the current of cooling air can, when usingcondenser tubes of the same length and with similar heat-exchangingsurfaces, also have a considerably larger passage cross section, forexample larger by M1, or 2/3, than the tubes of the rows of tubesarranged thereafter. In this case, however, it is particularlyadvantageous for the ow cross section of the condenser tubes in the rowsof tubes arranged one behind the other in the direction in which thecooling air ows, to be dimensioned in the same ratio to the drop intemperature actually available between the steam admis sion temperaturein the region of the distribution chainber and the mean cooling airtemperature in the region of the actual row of tubes.

The object of the invention can also be attained by using a combinationof two or more of the means indicated above.

Several preferred embodiments of the invention are illustrated by way ofexample in the accompanying drawings, in which:

FIG. l is a side elevation showing a complete condenser plant;

FIG. 2 is a top plan view and a horizontal section on line II--II ofFIG. 1;

FIG. 3 is a vertical section, on a larger scale, on line III- III ofFIG. 2;

FIG. 4 is a diagrammatic front elevation of a condenser element;

FIG. 5 is a vertical section on line V-V of FIG. 4;

FIG. 6 shows, on a larger scale, a portion of FIG. 5 with ribbed tubesand throttle nozzles inserted therein;

FIG. 7 shows, on a larger scale, a portion of FIG. 5 with throttlediaphragms inserted in the ribbed tubes;

FIG. 8 shows, on a larger scale, a section of FIG. 5 with a false bottomplate arranged in the steam distribution chamber and provided withapertures;

FIG. 9 shows the false bottom plate according to FIG. 8 in perspectiveview;

FIG. lO is a cross section through the upper part of a modified form ofconstruction of a condenser element with tubes with differentheat-exchanging surfaces, and

FIG. 1l is a cross section similar to FIG. l0 showing a condenserelement with tubes with diierent passage cross sections.

As shown in FIGS. l and 2 a steam discharge conduit i from a steamturbine Z which drives, for example, an electric generator 3, isconnected to a symmetrically branched steam feeding system 4. Thebranches of said steam feeding system 4 are of similar construction, thecross-sectional ow area of the steam feed conduit 4 being reduced instages in proportion to the quantities 'of steam lcd ol, so that theflow speed of the steam along the `entire length of the steam feedconduit i is substantially the same. As can be seen from FIG. 1 thesteam feeding system 4 connected to the discharge conduit 1 is laidunder the oor and has four connection pieces 5 arranged at uniformdistances apart and extending perpendicularly to the floor. Twodiverging, similarly constructed and coaxially arranged steamdistribution conduits 6 and 6a are connected to each of the endconnecting pieces 5 of the steam feed conduits 4. A double row ofcondenser elements 7 and 7a is connected to each of the steamdistribution conduits 6 and 6a.

The condenser elements 7 and 7a are, as can be seen from FIG. 3,arranged at an incline to each other in roofshape and connected at theirends close to each other to the steam distribution conduits 6 and 6aextending in the longitudinal direction of the double rows. and at theirends away from each other to condenser collecting conduits and Saextending parallel thereto. The condenser elements 7 and 7a inclinedtowards each other .in roofshape form a substantially equilateraltriangle in cross section, and on the base of this triangle propellerblowers 9 of relatively large diameter are arranged extending in ahorizontal plane. The propeller blowers 9, as can be seen from FIG. 2,are arranged with but slight lateral clearance under the condenserelements 7 and 7a united in double rows and are equipped with individualdrives 1i) which can be adjusted independently of each other. ln thismanner the number of revolutions of the individual propeller blowers 9can be independently regulated. ln addition the angle of incidence ofthe blades of the propeller blowers can be adjusted, although this isnot shown in the drawings, in order to be able in this manner toregulate the quantity of air delivered by the individual blowersindependently of each other.

As can be seen from FIGS. 1 to 3, the condenser elements 7 and 7aarranged on both sides of the connection pieces 5 of the steam feedingsystem 4 and united in double rows, are in each case arranged above alarge suction chamber 11 open on all sides and which has suc tionapertures 12 extending substantially over their entire outer sides. Thepropeller blowers 9 suck air from the atmosphere through the suctionapertures 12 provided in the sides of the suction chamber 11 and forceit upwards in substantially vertical direction through the condenserelements 7 and 7a arranged above the propeller blowers 9.

Instead of the condenser elements 7 and 7a being arranged as shown inFIGS. 1 to 3, it is obvious that the invention can be carried out withcondenser elements arranged in some other manner. The only important factor is that the condenser must have several condenser elements which areparallel connected in as far as the steam to be condensed is concernedand which are externally cooled by a positively circulated air currentand in which each of the condenser elements has at least two rows ofsubstantially parallel condenser tubes arranged one behind the other ata distance apart in the direction in which the cooling air stream iscirculated, the condenser tubes of each condenser element beingconnected in parallel up to a common steam distribution chamber and to acommon condensate collecting chamber.

An example of a form of construction of a condenser element of this typeis illustrated diagrammatically in FIGS. 4 and 5. Each of the condenserelements has a relatively large number of ribbed tubes 13 of circularcross section arranged parallel to each other at a distance apart, whichtubes, as can be seen from FIG. 5, are arranged infour rows 14, 15, 16and 17 connected up in series at a distance apart in the direction ofthe cooling air ow x. It is evident that two, three or more than fourrows of ribbed tubes arranged one behind the other in the direction x inwhich the cooling air ows, can also be used instead of the four rows ofseries connected ribbed tubes 13. Moreover, it is also possible to usetubes of elliptical or oval cross section instead of tubes with circular cross section. In this case the tubes will be so arranged thattheir long cross-sectional axis lies in the direction x in which thecooling air tlows.

All the ribbed tubes 13 of each condenser element are connected at theirupper end to a common steam distribution chamber 18 and at their lowerend to a common condensate collecting chamber 19. The steam distributionchambers 1S of the condenser elements are connected to the steamdistribution conduits 6 and 6a by connection pieces 20 of large crosssection extending substantially over the entire length of the steamdistribution chambers 1S. The steam distribution conduits 6 and 6a have,as can be seen from FIGS. 1 and 2, a cross-sectional shape taperingconically in the direction of ow y of the steam, the cross-sectionalreduction being in proportion to the amount of steam led off to thecondenser elements arranged side by side in the longitudinal directionof the distribution conduits 6 and 6a. The steam to be condensedis fedvia the connection pieces 20 in the direction a at a temperature ofabout 40 C. into the steam distribution chambers 18.

The condensate collecting chambers 19 of the condenser elements areconnected to the condensate collecting conduits 8 and 8a by connectionpieces 21. These connection pieces 2.1, contrary to those of the exampleillustrated in FIGS. 4 and 5, can have a considerably larger passagecross section. The condensate collecting chambers 19 are also connectedby connection pieces 22 arranged laterally of the collecting chambers19, to an air exhaust conduit 23 which leads to an air exhausting device23a as can be seen from FIGS. l and 2. This air exhausting device 2351,*

constructed in known manner, produces the vacuum necessary for thecondensation of the steam. In this arrangement a common air exhaustercan be provided for all condenser elements of the condenser, butlikewise a separate air exhauster may be provided for example for eachof the steam distribution conduits 6 and 6a. Moreover, it is alsopossible to utilize the condensate collecting conduits 8 and 8u at thesame time as suction lines and Ito connect the air exhausting device ordevices directly to the condensate collecting conduits S and 8a. Withthe aid of the air exhausting devices coordinated to the condenser, anabsolute pressure of for example 0.05 atm. is produced in the condenserelements.

In the form of construction illustrated in FIGS. 4 and 5, the condensertubes 13 of all rows of tubes 14, 15, 16, 17 Vare all of the same lengthand have similar heat-exchanging surfaces and passage cross sections.The rows of tubes 14, 15, 16, 17 are arranged parallel to each other andat the same distance apart. Each row of tubes 14, 15, 16, 17 consists ofa relatively large number of likewise parallel condenser tubes 13arranged at the same distance apart in lateral direction.

In the case where the condenser tubes 13 of all the rows of tubes 14,15, 16, 17 receive the same quantity of steam, dierent condensationconditions exist in the individual rows of tubes owing to the differentdrop in temperature between the steam temperature in the region of thedistribution chambers 18 and the cooling air temperature in the regionof each individual row of tubes 14, 15,16, 17. As the `drop intemperature between the steam and the air is relatively greatest in thetubes of the row of tubes 14 rst brushed by the cooling air, thecondensation process in the tubes 13 of this row of tubes 14 alreadyfinishes at a relatively great distance from the ends of the tubesleading into the condensate collecting cham-ber 19. When all the rows oftubes are uniformly fed with steam, only the upper portion of the lengthof the condenser tubes 13 of the row `of tubes 1d, which is shownwithout cross-hatching in FiG. 5, is fully utilized for the condensationof the steam, whereas in the lower cross-hatched portion of the lengthof the condenser tubes of the row 14, the condensate is subjected tounnecessary undercooling. Owing to the fact that the drop in tempcraturebetween the steam temperature in the region of the distribution chamber18 and the cooling air temperature in the region of the individual rowsof tubes 15, 16, 17 becomes less from row to row of the tubes, theboundary between the condensation region which is not cross-hatched andthe subcooling region which is crosshatched is displaced more and moretowards the ends of the tubes leading into the condensate collectingchamber 19.

In the case of the condensers hitherto generally 4used the strength ofthe cooling air current in relation to the actual atmospherictemperature is generally so chosen that the condensation process in therow of tubes 17 located at the end of the cooling air current,terminates near the lower end of the condenser tubes. Consequently, ofthe whole of the heat-exchanging surface of the condenser tubes 13 ofthe rows of tubes 14, 15, 16 only the section located above thecross-hatched subcooled region is utilized for the condensation of thesteam in the known condensers. In the case of low atmospherictemperatures,

6. for example 20 C. and below, ice plugs are formed in the subcooledzones and choke these tubes so that nally only the last row of tubes 17in the direction of the cooling air current is available for thecondensation of the steam.

In order to overcome these objections, throttle arrangements can bedetachably tted in the ends of the tubes of the second, third and fourthrows of tubes 15, 16, 17 in the direction x in which the cooling air`flows, which ends lead `from the steam distribution chamber 18, asillustrated in FIGS. 6 and 7. In the form of construction illustrated inFIG. 6 the throttle arrangements consist of nozzles 24, 25, 26 whichhave a different passage cross section in the individual rows of tubes.The passage cross section of the condenser tubes 13 of the row or tubes14 tirst -brushed by the cooling air current and also of the nozzles 24,v25, 26 of the rows of tubes 15, 16, 17 is gauged in the same ratio tothe drop in temperature between the steam temperature in the region ofthe steam.

distribution chamber 18 and the mean cooling air ternperature in theregion of the actual row of tubes 14, 15, 16, 17. Thus the condensertubes in the rows of tubes 14, 15, 16, 17 are supplied with `dilferentquantities of steam proportional to the drop in temperature between thesteam admission temperature and the mean cooling air temperatureactually available in the region of the actual row of tubes, so that inall the rows of tubes the condensate enters the condensate collectingchamber 19 at approximately the same temperature. At the samey time thestrength of the cooling air current is adapted, by regulating theblowers 9 according to the actual atmospheric temperature, to the totalquantity of steam to be condensed in a condenser element so that thecondensation terminates inall the rows of tubes.14, 15, 16, 17 at ashort distance from the ends of the tubes leading into the condensatecollecting chamber 19, with -the result that no appreciable subcoolingof the condensate takes place.

Instead of the nozzles 24, 25, 26 used in FIG. 6, the steam distributionto the condenser tubes 13 of the individual rows of tubes 14, 15, 16, 17arranged one behind the other in the direction of ow x of the coolingair, can be regulated by diaphragrns 27, 28, 29 (FIG. 7) or by otherdevices narrowing the cross-sectional passage area of the tubes. Thediaphragms 27, 2S, 29 arealso detachably fitted in the ends of thetubes. In the case ot' elliptical ribbed tubes with end sections ofcircular cross section, the diaphragms 27, 2S, 29 can also be looselyinserted in the ends of the tubes. The passage cross section of thecondenser tubes 13 of the first row' 'of tubes 1a, as well as thediaphragrns 2.7, 2S, 29 of the rows of tubes 15, 116, 17 is gradedproportionately equal to the actually available dropI in temperaturebetween the steam temperature in the region of the steam distributionchamber 18 and the mean cooling air temperature in the region of theactual row of tubes 14, 1:7, 16, 17. At the same time the strength ofthe cooling air current is also regulated, depending upon the actualatmospheric temperature, according to the total quantity of steam to becondensed in the condenser element so that the condensation terminatesin all rows of tubes at a short distance from the ends of the tubesleading into the condensate collecting chamber 19. The condenser tubes13 of ali the rows of tubes 14, 15, 16, 17 are, in the form ofconstruction illustrated in FIGS. 6 and 7, all of the same length, havesimilar heat-exchanging surfaces and, apart from the throttle devices 24to 29 in their upper end, the same passage cross section. The radialribs provided on the outer side of the condenser tubes 13 are designatedby 30 and are all of the same surface area and distributed at uniformdistances apart over the entire length of the condenser tubes 13.

In the form of construction illustrated in FIGS. 8 and 9, the condenserelement also has four rows of condenser tubes 13 arranged one behind theother in the direction x in which the cooling air flows, which condensertubes are all of the same length, have similar heat-exchanging surfacesand the same passage cross section. As can be seen from FIG. 8, a falsebottom plate 31 extending substantially parallel to the plane of thetube mouths is arranged in the distribution chamber 18 and provided withapertures 32, 33, 34, 35 opposite the mouths of the tubes. The passagecross section of these apertures 32, 33, 34, 35 is progressively smallerfrom row to row of tubes in the direction x in which cooling air tiows,proportionately to the actually available drop in temperature betweenthe steam admission temperature in the region of the steam distributionchamber 18 and the mean cooling air temperature in the region of theactual row of tubes 14, 15, 16, 17. By this arrangement it is alsopossible for the condenser tubes in the rows of tubes 14, 15, 16, 17 tobe supplied with different quantities of steam which are proportional tothe actually available drop in temperature between the steam admissiontemperature vand the mean coe-ling air temperature in the region of theactual row of tubes. The condenser tubes 13 are, in the exampleillustrated in FIG. 8, provided along their entire length with radialtubes 30 on their outer side.

In the case of the atmospheric temperature being for example 20 C. andthe steam temperature for example +40 C. in the region of the steamdistribution chamber 1S, susbtantially the following conditions can beassumed in the case of the forms of construction illustrated in FIGS. 6to 9:

The mean cooling air temperature in the region of the individual rows oftubes 14, 15, 16, 17 arranged one behind the other in the direction ofow x should, under the given conditions, be 15 C. for the row of tubes14, 6.5" C. for the row of tubes 15, -0.5 C. for the row of tubes 16 and+35" C. for the row of tubes 17. In the rows of tubes the following meandrop in temperature is available for the condensation of the steam:

Row 14=55 C. Row 15=46.5 C. Row 16=40.5 C. Row 17=36.5 C.

The passage cross section of the nozzles 24 (FIG. 6) or of thediaphragms 27 to 29 (-FIG. 7) or of the aper- 32 to 35 in the falsebottom 31 (FIGS. 8 and 9) are so stepped down that the quantities ofsteam distributed to the condenser tubes of the rows of tubes 14, 15,16, 17 are as 55:46.5:40.5:36.5.

The form of construction of a condenser element illustrated in FIGS. land l1, is provided with three rows of tubes 14, 15, 16 arranged onebehind the other in the direction of flow of the cooling air x. In theexample illustrated in FIG. the ribbed tubes 13 in the rows of tubes 14,15, 16 are all of the same length and have the same passage crosssection. Furthermore, the ribbed tubes 13 in all the rows of tubes aresupplied with the same quantity of steam. The heat-exchanging surfacesof the ribbed tubes are, however, of diterent `dimensions in theindividual rows of tubes 14, 15, 16. In the row of tubes 14 tirstbrushed by the current of cooling air, the condenser tubes 13 have aheat-exchanging surface which is considerably smaller than that of thetubes of the row 15, the heat-exchanging surface of which is in turnconsiderably smaller than that of the row of tubes 16. Furthermore, thespacing of the ribs 30 in the individual rows of tubes 14, 15, 16differs in the form of construction illustrated in FIG. 10. It ishowever also possible, while retaining equal spacing in the individualrows, to make the ribs of different sizes. The heat exchanging surfaceof the condenser tubes 13 in the rows of tubes 14, 15, 16 is inverselyproportional to the available drop in temperature between the steamadmission temperature in the region of the steam distribution chamber 18not shown iin FIG. l0, and the mean 8, cooling air temperature intheregion of the actual row of tubes 14, 15, 16. In the event of theavailable drop in temperature in the rows of tubes 14, 15, 16 being 40,30 and 23 C., respectively, the heat-exchange surfaces of the condensertubes 1,3 -in the rows of tubes 14, 15, 16 should be as l/40z1/3021/23.

In the example illustrated in FIG. 11, the condenser tubes 13 in therows of tubes 14, 15, 16 arranged one bchind the other in the directionof flow of the cooling air x, are of the same length and have the sameheat-exchanging surface area but have passage cross sections ofdifierent sizes. The passage cross section of the condenser tubes in therows of tubes 14, 15, 16 is proportionately equal in each actual row oftubes to the drop in temperature between the steam admission temperaturein the region of the steam distribution chamber and the mean cooling airtemperature in the region of said actual row of tubes, so that a steamdistribution proportional to the actually available drop in temperatureis set for the condenser tubes 13 of the rows of tubes 14, 15, 16. lnthe event of the drop in temperature between the cooling air and thesteam in the steam distribution chamber being 40 C. in the region of therow of tubes 14, 30 C. in the region of the row of tubes 15 and 23 C. inthe region of the row of tubes 16, the passage cross sections of thecondenser tubes in the rows of tubes 14, 15, I6 should be in a ratio of40:30:23. The size of the surface area and the spacing of the ribs 30 ofthe condenser tubes 13 is so chosen in the individual rows of tubes 14,15, 16 that the heat-exchanging surfaces of all the condenser tubes areof the same size.

From the above detailed description of the invention, it is believedthat the construction will at once be apparent, land while there areherein shown and describe/.l several` preferred embodiments of theinvention, it is nevertheless to be understood that minor changes may bemade therein Without departing from the spirit and scope of theinvention as claimed.

I claim:

1. In a surface condenser for condensing steam by a stream of coolingair, in combination, a plurality of conduit means connected in parallel,each conduit means including a row of conduits for conducting the steamtransverse to the direction of the stream of air, said rows of conduitsbeing located in planes extending transverse to said direction anddistributed along the length of the stream of air so that the stream ofcooling air successively passes over the outer surface of each of saidconduit means whereby the temperature of the air is increased, saidconduits of each row of conduits being substantially identical, andhaving substantially the same heat-exchanging surface, and the conduitsof all said rows of conduits being diiferently shaped and arranged insuch a manner that the amounts of steam passing through each conduitseparately, and through all conduits of each row across con- 'secutiveequal portions of said stream of air decrease in said direction of thestream of air corresponding to the decreasing cooling capacity of thestream of air so that the condensate formed in each of said conduitmeans of the steam entering all said conduit means at the sametemperature has substantially the same desired temperature.

2. In a vsurface condenser for condensing steam by a stream of coolingair, in combination, a plurality of conduit means connected in parallel,each conduit means in cluding a row of substantially identical conduitsfor conducting the steam, `said rows of conduits being located in planesextending transverse to the direction of the stream of air and beingdistributed along the length of the stream of air so that the stream ofcooling air 'successively passes over the outer surface of each of saidconduit means whereby the temperature of the air is increased; andthrottling orice means arranged in said conduits for throttling the flowof steam through said conduit means, the throttling orifice means in theconduits of each row being substantially identical, and the throttlingorifice means of all said rows lbeing differently shaped in such amanner that different amounts of steam flow through each of said conduitmeans and that the total amounts of steam passing through said conduitmeans across consecutive equal portions of said stream of air decreasein said direction of the stream of air corresponding to the decreasingcooling capacity of the stream of air so that the condensate formed ineach of said conduit means of the steam entering all said conduit meansat the same temperature has substantially the same desired temperature.

3. In a surface condenser for condensing steam by a stream of coolingair, in combination, a plurality of conduit means, each conduit meansincluding the same number of tubes arranged in a row for conducting thesteam transverse to the direction of the stream of air, said rows oftubes being located in planes extending transverse to said direction anddistributed along the length of the stream of air so that the 'stream ofcooling air successively passes over the outer surface of each of saidconduit means whereby the temperature of the air is increased, saidtubes being substantially identical; and throttling oriiice means forsaid tubes, the throttling orice means for the tubes of each conduitmeans being identical, and -the throttling orifice means for the tubesof dierent conduit means being dierently shaped in such a manner thatdifferent amounts of steam flow through each row of tubes and that thetotal amounts of steam passing through said conduit means acro'ssconsecutive equal portions of said stream of air decrease in saiddirection of the stream of air corresponding to the decreasing coolingcapacity of the stream of -air so that the condensate formed in each ofsaid conduit means has substantially the same desired temperature.

4. In a surface condenser for condensing steam by a stream of coolingair, in combination, a plurality of conduit means, each conduit meansincluding the same number of tubes arranged in a row for conducting thesteam transverse to the direction of the stream of air, said rows oftubes being located in planes extending transverse to said direction anddistributed along the length of the stream of air so that the stream ofcooling air successively passes over the outer surface of each of saidconduit means whereby the temperature of the air is increased, saidtubes being substantially identical; and detachably mounted ythrottlingorifice means for said tubes, the throttling orice means for the tubesof each conduit means being identical, `and the throttling orifice meansfor the tubes of different conduit means being diferently shaped in sucha manner that different amounts of steam flow lthrough each row of tubesand that the total amounts of steam passing through said conduit meansacross consecutive equal portions of said stream of air decrease in saiddirection of the stream of air corresponding to the decreasing coolingca- 10 pacity of the stream of air so that the condensate formed in eachof said conduit means has substantially the same desired temperature.

5. In a surface condenser for condensing steam, in combination, blowermeans for producing a stream of air owing in a selected direction; aplurality of conduit means spaced different distances from said blowermeans, each conduit means including the same number of tubes arranged inla row for conducting the steam transverse to the direction of thestream of air, said rows of tubes being located in planes extendingtransverse to said ydirection and distributed along the length of thestream of air so that the stream of cooling air successively passes overthe outer surface of each of said conduit means whereby the temperatureof the air is increased, said tubes being substantially identical; anddetachably mounted throttling orice means for said tubes, the throttlingorifice means for the tubes of each conduit means being identical, andthe throttling orifice means for the tubes of different conduit meansbeing differently shaped in such .a manner that different amounts ofsteam flow through each row of tubes and that the total amounts of steampassing through said conduit means across consecutive equal portions ofsaid stream of air decrease in said direction of the stream of aircorresponding to the decreasing cooling capacity of the stream of air sothat the condensate formed in each of said conduit means hassubstantially the same desired temperature.

6. A surface condenser as set forth in claim 1 wherein said conduitmeans have different cross sectional areas decreasing in said directionof the lstream of air.

7. A surface condenser as set forth in claim 1 wherein said conduits ofthe first row of conduits in the direction of said stream of air overwhich the air passes first have cross 'sections one quarter to twothirds greater than the cross sections of the row of conduits nextfollowing in said direction of the stream of air.

References Cited in the file of this patent UNITED STATES PATENTS1,597,720 Carrier Aug. 31, 1926 1,627,265 Bancel May 3, 1927 1,760,505Lea May 27, 1930 1,915,805 Sutcliie June 27, 1933 2,006,649 Modine July2, 1935 2,107,478 Happel Feb. 8, 1938 2,263,397 Rathbun Nov. 18, 19412,587,720 Fritzberg Mar. 4, 1952 2,613,065 Didier Oct. 7, 1952 FOREIGNPATENTS 732,492 Great Britain Iune 22, 1955

1. IN A SURFACE CONDENSER FOR CONDENSING STEAM BY A STREAM OF COOLINGAIR, IN COMBINATION, A PLURALITY OF CONDUIT MEANS CONNECTED IN PARALLEL,EACH CONDUIT MEANS INCLUDING A ROW OF CONDUITS FOR CONDUCTING THE STEAMTRANSVERSE TO THE DIRECTION OF THE STREAM OF AIR, SAID ROWS OF CONDUITSBEING LOCATED IN PLANES EXTENDING TRANSVERSE TO SAID DIRECTION ANDDISTRIBUTED ALONG THE LENGTH OF THE STREAM OF AIR SO THAT THE STREAM OFCOOLING AIR SUCCESSIVELY PASSES OVER THE OUTER SURFACE OF EACH OF SAIDCONDUIT MEANS WHEREBY THE TEMPERATURE OF THE AIR IS INCREASED, SAIDCONDUITS OF EACH ROW OF CONDUITS BEING SUBSTANTIALLY IDENTICAL, ANDHAVING SUBSTANTIALLY THE SAME HEAT-EXCHANGING SURFACE, AND THE CONDUITSOF ALL SAID ROWS OF CONDUITS BEING DIFFERENTLY SHAPED AND ARRANGED INSUCH A MANNER THAT THE AMOUNTS OF STEAM PASSING THROUGH EACH CONDUITSEPARATELY, AND THROUGH ALL CONDUITS OF EACH ROW ACROSS CONSECUTIVEEQUAL PORTIONS OF SAID STEAM OF AIR DECREASE IN SAID DIRECTION OF THESTREAM OF AIR CORRESPONDING TO THE DECREASING COOLING CAPACITY OF THESTREAM OF AIR SO THAT THE CONDENSATE FORMED IN EACH OF SAID CONDUITMEANS OF THE STEAM ENTERING ALL SAID CONDUIT MEANS AT THE SAMETEMPERATURE HAS SUBSTANTIALLY THE SAME DESIRED TEMPERATURE.